Extensible ladder



A. ZERLINIL EXTENSIBLE LADDER.

APPLICATION FILED JUNE 26. 1919.

1,851,146. PatentedAug. 31,1920.

2 SHEETSSHEET 1.

A fforne I A. ZERLINI.

'EXTENSIBLE LADDER.

APPLICATJON F( LED JUNE 26, 1919.

Patented Aug. 31, 1920.

PATENT OFFICE.

ALESSANDRD ZERLINI, or BRESCIA, ITALY.

EXTENSIBLE LADDER.

Application filed June 26, 1919.

T0 aZZ whom it may concern:

lie it known that l, ALnssANnno ZERLINI, manufacturer, of llrescia, Italy, have invented certain new and useful Improvements in and Relating to Extensible Ladders, of which the following is a specification.

The invention relates to extensible ladders.

An object of the invention is the construction of a ladder constituted of two or more portions, said portions being mounted on one another and provided with means to form up both an extended, and a selfstanding ladder.

The invention will be better understood with reference to the annexed drawings of which:

Figures 1 and 2 are perspective views of the two ladder-portions.

Fig. 3 represents said ladder portions mounted one on the other to constitute an extensible ladder.

Fig. 4. shows the same two portions mounted one on the other to constitute a selfstanding ladder.

The same reference numerals designate like parts thoughout the drawing.

The ladder comprises the main flight 1- and the secondary flight 2-. The main flight is constituted of beams 3- of rectangular cross section and steps 41-; and the secondary flight is constituted of beams -5 and steps 6-.

The inner distance d between beams 3 is equal to the outer distance e-- between beams 5 so that portion -2 may be mounted on portion -1 and slide within the same along on steps -4.

Beams -3 are provided with longitudinal guiding slots 7 to receive metallic projections -8 fastened to the lower ends of beams 5- by means of stirrups -lO-.

About the upper end of flight -1-- is mounted on supports 11 fastened to beams 3-, a rock shaft -12 provided with arms -1.3. Said shaft receives angular motions through rod 14 slidably connected to a beam -3-, said rod being kept on said beam by the heads of nails l5- engaging slots -l6 in said rod.

The reciprocating movement of rod ll is converted into angular movement of shaft 12 which is obtained through lever arm -1S projecting from said shaft, the end of which engages slot 17 in rod -14l-.

Flight 2 bears hinge-slots-IQ- one Specification of Letters Patent.

Patented Aug 31, 1920.

Serial No. 395,980.

of which is adapted to be bridged or closed by the upper end --2 of an endwise movable rod -2l., the lower end of which is bent to form a linger-piece 22.

The ladder is used as follows:

Flight 2 is mounted on flight l-, while projections 8 enter slots 7--. By sliding portion 2 upward, the steps 6 will successively strike arms 13 which will first be swung upward and backward as each step strikes them, so as to give free passage to the step and then drop back, as the step passes beyond them, to their resting position on the topmost step -4iof flight -l, thus preventing a backward sliding of flight Qr-.

To dismount portion -2- from portion -1-, the former is pushed forward until the step -6- resting on the arms -l3- 7 will allow the latter to be rotated to a posi' tion parallel to beams -3-- by means of rod -14 and its finger-piece 23.

Thereupon flight -2- is pulled backward until projections 8 are withdrawn from slots -7.

To mount the two flights as a self standing ladder, hinge-slots 19-- are connected to shaft -12- while the upper ends of beams 5- are inserted between said shaft and the step -4tbehind it. Said shaft is held in place in said slots by the end -20- of :I'OCl 21-, which latter is manipulated by means of its finger-piece -2Q.

Having now particularly described the nature of my invention and the manner in which the same should be used I claim 1. A ladder, comprising a pair of separable flights, each embodying connected side beams and steps; one flight being provided adjacent its top with a horizontal cross-shaft which is attached to the side beams thereof in front of and in spaced relation to the top most step; the other flight having inwardlyextending slots provided in its side beams adjacent their upper ends to receive the adjacent portions of said shaft, and also having retaining means associated with one of said slots to bridge the same and thereby lock said shaft against displacement.

2. A. ladder, comprising a pair of separable flights, each embodying connected side beams and steps; one flight being provided adjacent its top with a horizontal cross-shaft which is attached to the side beams thereof in front of and in spaced relation to the topmost step; the other flight having inwardlyextending slots provided in its side beams adjacent their upper ends to receive the adjacent portions of said shaft and a rod slidably arranged against one side beam of the last-named flight for movementinto position to extend across and thereby close the 7 adjacent slot, so as to lock said shaft against displacement. Y

3. A ladder, comprising relatively fixed and-movable flights each embodying connected side beams and steps; the side beams of theimovable flight adapted to fit slidably said topmost step and to be struck and signature, in

rocked forward by the successive steps of the slidableflight during its upward movement and to drop back to normal position as the steps pass beyond it; an endWise-movable rod slidably mounted on one of the side beams of the fixed flight and formed adjacent its upper end with a longitudinal slot; and an arm on said vshaft separate from the first-named arm engaged in said slot to permit the rocking movements of said shaft during and consequent upon the endwise movement of said rod.

In testimony whereof I have affixed my presence of two WltlH-ZSSGS; ALESSANDRO ZE'RLINI.

Witnesses E. E. GUANIN, IVAN LAVRETSKY. 

